The movie also marks the local film debut of acclaimed France-based auteur Joo Ji-hong, whose filmography includes ``Le Mal de Dents'' starring Kristin Scott Thomas. "Maybe" will premiere at the 14th Pusan (Busan) International Film Festival (PIFF), which runs from Oct. 8 to 16, before a nationwide theatrical release Oct. 22.

Best known as a former member of K-pop band Fin.K.L, Sung has become a regular leading lady on the small screen, most recently appearing in the big budget TV soap ``Swallowing the Sun'' (SBS).

``I've always wanted to do movies but it seemed too overwhelming, having to fill the huge screen with your face and acting. I could not have done it without the support of the director, Jang Hyuk and the crew,'' Sung told reporters at a promotional event Monday in Seoul.

``Singer-turned-actors tend to be less fearful of cameras, which is an advantage. But because they are often high-profile when they make their acting debut they are often prone to cold criticism. The criticism can be hurtful, but I've realized that it is a sign of interest and one must overcome it. I'm also trying my best,'' she said.

When asked about what the crossover from TV soaps to films was like, the 28-year-old said she was able to focus better on the set. ``The director and crew create an environment for you to completely immerse yourself in, to focus only on acting. (My character) May is silent and introverted, so the crew tried to help me stay in character by not talking to me as much. It's a pity though because I didn't get to befriend the crew, and I got a little bored later on because people didn't speak to me,'' she said.

To prepare for her role as a quiet woman who was adopted by overseas parents at a young age, she said she spent a lot of time alone and watched documentaries about adoption. She also practiced her English skills.

The director said that ``contrary to public opinion, Sung has a knack for playing out emotions'' and promised that the movie would ``show a new side of the actress.''

``Maybe'' is about May, who returns to Korea in search of her birth family. However, she is disappointed to learn that both of her parents had died in a car accident. As she turns away deeply disappointed, she picks up a wallet, which, coincidentally, belongs to Eun-seol (Jang), the taxi driver that drove her earlier that day.

Eun-seol, on the other hand, suffers from a rare terminal disease from which the heart can stop beating any moment, and thus lives each day expecting the worst. The two strangers recognize in each other a kindred spirit suffering from a painful past, and empathy eventually grows into love.

Jang said the movie is not so much about the agony of being seriously ill, but about interacting with the everyday things of life ― such as love ― while dealing with a particular health condition. Joo said that Jang was a versatile actor who could express the diverse emotions required of the part.

The 32-year-old actor said he was fortunate to work with Sung. ``She is a very diligent actress and our harmony was wonderful,'' he said. ``I must have done a lot of good things in my past life because I get to work with the most beautiful actresses,'' chuckled Jang, who has starred opposite screen beauties before, such as Jun Ji-hyun in ``Windstruck.''

Meanwhile the two leading actors made headlines by investing their guarantees into the film's production cost.